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sizeof single struct member in C
...ic way to do it, another would be to use a macro like this:
#define member_size(type, member) sizeof(((type *)0)->member)
and use it like this:
typedef struct
{
float calc;
char text[255];
int used;
} Parent;
typedef struct
{
char flag;
char text[member_size(Parent, text)...
Get the value of an instance variable given its name
...
The most idiomatic way to achieve this is:
some_object.instance_variable_get("@#{name}")
There is no need to use + or intern; Ruby will handle this just fine. However, if you find yourself reaching into another object and pulling out its ivar, there's a reasonably good ...
C++中智能指针的设计和使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
...释放对象拥有权限、引用计数等，控制权转移等）。auto_ptr 即是一种常见的智能指针。
智能指针通常用类模板实现：
template <class T>
class smartpointer
{
private:
T *_ptr;
public:
smartpointer(T *p) : _ptr(p) //构造函数
{
}
T& oper...
Can someone explain Microsoft Unity?
...object gets created.
Without IoC:
public class MyClass
{
IMyService _myService;
public MyClass()
{
_myService = new SomeConcreteService();
}
}
With IoC container:
public class MyClass
{
IMyService _myService;
public MyClass(IMyService myService)
{
_myS...
python list in sql query as parameter
... cursor.execute(f'SELECT name FROM students WHERE id IN ({','.join('?' for _ in l)})', l). @bobince, you should also remark in your solution that using ? is the safe way to go in terms of avoid SQL injection. There are a lot of answers here that are vulnerable, basically any that concatenates string...
How to compile for Windows on Linux with gcc/g++?
...torial here at the Code::Blocks forum. Mind that the command changes to x86_64-w64-mingw32-gcc-win32, for example.
Ubuntu, for example, has MinGW in its repositories:
$ apt-cache search mingw
[...]
g++-mingw-w64 - GNU C++ compiler for MinGW-w64
gcc-mingw-w64 - GNU C compiler for MinGW-w64
mingw-w6...
Maven build failed: “Unable to locate the Javac Compiler in: jre or jdk issue”
I have my JAVA_HOME set to:
32 Answers
32
...
Read text file into string array (and write)
...n err
}
defer file.Close()
w := bufio.NewWriter(file)
for _, line := range lines {
fmt.Fprintln(w, line)
}
return w.Flush()
}
func main() {
lines, err := readLines("foo.in.txt")
if err != nil {
log.Fatalf("readLines: %s", err)
}
for i, line :...
/bin/sh: pushd: not found
... If it's just a oneliner, the following may also work (cd /new_path ; command )
– barney765
Aug 5 '17 at 7:31
...
List of foreign keys and the tables they reference
...
The referenced primary key is described in the columns r_owner and r_constraint_name of the table ALL_CONSTRAINTS. This will give you the info you want:
SELECT a.table_name, a.column_name, a.constraint_name, c.owner,
-- referenced pk
c.r_owner, c_pk.table_name r_ta...